HIV’s RISC-y Behavior

July 1st, 2009. There’s nothing restricting miRNAs to targeting just endogenous mRNAs. So it’s no surprise to find that expression of miR-29a – which targets the 3’UTR of HIV-1 mRNA -- increases during HIV infection.
 
Researchers from U Mass Med School in Worchester, and the Burnham Institute for Medical Research in La Jolla, found that HIV mRNA hangs around with RNA-induced silencing complexes (RISCs) and cytoplasmic mRNA-processing-bodies (P bodies) in latently infected cells. Adding in more miR-29a enhances the relationship.
 
But when they block the action of miR-29a – with antisense oligos, for example – HIV replication goes up. The same thing happens when they disrupt the integrity of the P bodies themselves. So it looks like miR-29a keeps HIV from going postal, which in turn helps it to evade immune detection and eradication by antiviral treatments.

Check out all the details at Molecular Cell June 26, 2009.